Apparatus for extraction of aluminium



March 5, 1957 P. MORIZE APPARATUS FOR EXTRACTION 0 ALUMINIUM Filed May5, 1955 IN l/EN TOR. Pierre Mar/2e M A HIS Arron/5Y greater than:are=formed, located inside the of a bell shaped United States 2,783,991APPARATUS FOR EXTRACTION F ALUMINIUM Application May 5, 1955, Serial No.506,339 7 Claims (Cl. 26635) The present invention relates to a devicefor the commercial extraction of aluminium from its alloys or frommaterial in which it is contained.

This device is intended for carrying into etfect the known method whichconsists in the reaction on these alloys or materials, at a suitabletemperature, of an aluminium halogenide so as to form a volatilesub-halogenide which is then cooled in a separate chamber in such a Wayas to cause the separation in the pure state of the aluminiurn absorbedand the liberation of the initial halogen salt, which is recovered andre-cycled.

This process has, up to the present time, been carried out at arelatively low pressure, which has given rise to ditficulties ofisolation and fluid-tightness together with the necessity of handling.large volumes of gas by reason of the low density of the gases at lowpressure.

Finally, since the period of contact of the halogenide withthe primarymaterial is short, the necessary balance of concentration of thesub-halogenide cannot be obtained.

{The present invention has for its object a device for carrying intoeffectaprocess of the kind referred to, device beingdesigned to overcomethe drawbacks mentioned above. Said deviceessentially comprises anuppertank adapted to contain the molten starting material and forming areaction chamber closed at its upper portion, its walls being maintainedat a temperature equal to or that of the said molten material ,to betreated, a supply conduit for bringing the aluminium halogenide througha gas-dividing member, one of the facesor" which is in contactwith thesaid molten metal, .anevacuation pipe forthe gaseous sub-halogenideswhich tank and passing through the said tank and the moltenmaterialina-fluid-tight manmet, a decomposition chamber in whichterminates the said evacuation pipe andta tan-k "for receiving puremetal drawn-ofi" from the base-of the said decomposition cham-'ber,-which is, in additiomprovided with-a conduit-for the recoveryoft-he gases which are-formed therein.

The reaction chamber is preferably formed by means member which plungesinto theupper tank. The said bell-shaped member'is advantageouslyprovided withtloublewalls providingan internal space adapted to receivea molten metal. Means are of course provided-toobtainthe necessarytemperatures in the various parts of theapparatus.

The gas-dividingmemberrnay be a plug made of porous materiaL'a plateprovided with a plurality offholes ora-multitnbular dilfuser.

The present invention is explained below in -greater detail withreference to the attacheddrawings which illustrate various embodimentsthereto, and in which:

(Fig. 1 is a view in'diagrammatic crqss-sectionof a device used in th eextractionpf ,alumi f n in accordance w t 'the r s i e ti nf'Fj -j anarealt r a ir tQEJ lsgtrtabefiiasatp agdevice of thejlkind referredgto.i

. single orifice closed by 2,783,991 estes! Me 5, we?

tion" of aluminium comprises a tank :1 bell 2 havin g double walls. i I"The tank is provided, on the one hand ,with anorifi ce cl sed bymeansof a porous plug3 which rr'iayals'o be, for .eiiample, afplat'epierced with a number ofholes orev multitubular diffuserfcommunicatingwitha onduit' which leads the halogen'id'e to a char iiber 5; H T '1 0nthe other hand, a furtherorificeisfiorrned in the said tank throughwhich is passed aif extraction ,t'ub made of material which is notattacked by'inl n minium such as, for example, calcined alum na. tube 6leads into a chamber 7, the-loweripar't'o constitutes a tank 3 and theupper part is'provid a conduit9 ,for evacuating the halogen com" nd. Thewhole assembly comprised by the porou's'plug 3, the tank 1 and the hell2, is maintained 'by ihfiatcr's'jfl at a temperature comprised between1100 and ;1 4Q'0, C. The chamber t7 and the tanks are maintained'by'aheater 38 at a temperature below 100 O 'C. but above the point ofaluminium, the tube d and .the'conduit f brought up to a temperaturewhich is at least equa to the temperature at which the vapour te l ionof th halo'gen In addition, the t I liquid primary material and is thusmaintainedlat this perature of this latter. V

The advantage of an arrangement of the present kind is that it enablesthe operation to, Qecarried out i a semi-continuous manner. It isactually po bl ;tract the primary material,

Wheth'e'r';ino1te or n time to time fromtheannular space bet the t n anfi W' fi wn it the a from the action of the halogen compound. material.

In the same way, it is possible to take off from the tank 8 thequantities of pure aluminiumlso,formed,.witliinthe limit n s s ar oimmein .a u tabteleyel .o f;thi liquid metalinthe chamber 7.

,Fig. 2 shows an alternative form of embodiment in which the tank -21 ofrefractory material, .such as 9 0% AlzO310% SiOz, for example, isprovided ,with ,a-ibell 22 v, of the same material. Theltankvispiercedwith a means of a porous plug 423 through which, thehalogen compound is passed through thei medium .of an iron tube -24,tintothe chamber 25' wlgich isfurthermore-limited ,by .a metal plug :21'c,;for example of molten lead, resting one, bed 2,111,. lheinature 5 fwhichwill be definedbelow. i

' An extraction tube 26 of, for,example, calcinedlaluniina leads'intoacham'oer'27 through a. plug 27,:zjatidla joint 27b; ,atthe lowerpart ofthe ch amber is; provided .a tank g of graphite for examplatromhwhichthel alogen compound can pass out at Z9 andlcan: here-cycled .att30. Thetank 21 issupportedon an insulatingbed zlacontained in a plate 2111,said bed being of granulatedtheatinsulating material.

@111 Fig. 3, thetank 31 ofrefractorvmaterial. O 10% Si02 for example) ,1is provided ,with a bell 32 of the same material. The tank ispiercedjwithtah orifice, provided witha porous plug 33;;3,.through;,which passes the halogen compound which is; ,led through anare made of aluminous porcelain and which pass through a plug 35a and ajoint 35b. v

The extraction tube 36' is of calcined alumina and enables thesub-halogenide to be evacuated, the halogenide being re-cycled aspreviously described, from a chamber formed above a tank (not shown) inwhich are collected respectively the halogen compound and the purealuminium product.

It will be seen that in all the forms of embodiment shown (comprising atank with a flat base, a raised base or a base with a depression) therehas been provided a fluid-tight passage for the tube which evacuates thesubhalogenides formed.

In Fig. l, the molten metal contained in the tank 1 itself serves as apoint providing the fluid-tight passage of the evacuation tube 6 intothe tank 7.

.'In Fig. 2, the molten metal contained in the tank 21, the molten lead21c and the joint 27bensure in combination the fluid-tight passage oitheconduit 26.

In Fig. 3, the molten metal contained in the tank 31 and the joint 35bcarry out the same function.

In Figs. 2 and 3, the arrangements for maintaining the temperature ofthe upper tank have not been shown and the details of the bell have alsonot been described, the latter being preferably a bell with double wallsidentical with that of Fig. 1.

In all the devices shown, the process is as follows: The halogencompound passes through the porous plug from the bottom to the top, thenecessary pressure being applied to it to that end, and bubbles into themolten primary material. The sub-halogenide which results from thereaction is collected in the upper portion of the bell and passes into adecomposition chamber at the base of which is collected the liquid purealuminium which forms in the tank provided for that purpose.

There are given below, by way of example, some results of the treatmentcarried out in the devices shown in Figs. 1 and 2.

Example 1 Using the device shown in Fig. l, a. bath of metal to bepurified was heated to 1250 C. for 3 hours 30 minutes, and through thisbath 275 grams of aluminium chloride were passed. 42 grams of purealuminium were subsequently collected and the efficiency of theoperation amounted to 38%.

Example 2 Using the arrangement shown in Fig. 2, a bath of metal to bepurified was heated to 1200 C. for hours, and through this metal bathwas passed 370 grams of aluminium chloride. 45 grams of pure aluminiumwere collected and the efiiciency of the operation was 30%.

' What we claim is:

1. An apparatus for commercial extraction of aluminum from aluminumcontaining alloys or like materials, comprising an upper tank adapted tocontain the starting material in a molten state up to a given level,forming a reaction chamber having a gas-tight upper part, means forheating said tank, a supply conduit adapted to be connected to a sourceof aluminum halogenide opening in the lower part of said tank through agasdividing member, an evacuation pipe passing through said tank in afluid-tight manner and having an upper end opening in the upper part ofsaid reaction chamber above the level of the starting material therein,and a lower end opening in a gas-tight decomposition chamber, a gasdraw-oil pipe opening in said decomposition chamber and a draw-off tankconnected to said decomposition chamber beneath said chamber, meansbeing provided for heating said decomposition chamber and draw-0E tank.

-2. An apparatus for commercial extraction of aluminum from aluminumcontaining alloys or like materials, comprising an upper tank adapted tocontain the substantially vertically,

starting material in a molten state up to a given level and having anopen upper part, a bell-shaped container having lateral walls extendingdownwards into said tank through said open upper part, below said levelof said starting material, thereby forming a reaction chamber withinsaid tank, means for heating said tank and said bell-shaped member, asupply conduit adapted to be connected to a source of aluminumhalogenide opening in the lower part of said tank through a gas-dividingmember, an evacuation pipe passing through said tank in a fluid-tightmanner and having an upper end opening in the upper part of saidreaction chamber above the level of the starting material thereinto, anda lower end opening in a gas-tight decomposition chamber, a gas draw-ofipipe opening in said decomposition chamber and a drawofi tank connectedto said decomposition chamber beneath said chamber, means being providedfor heating said decomposition chamber and draw-oil tank.

3. An apparatus as claimed in claim 1, in which said lateral walls ofsaid bell-shaped member are double walls providing an internal spaceadapted to receive a molten metal.

4. An apparatus for commercial extraction of aluminum from aluminumcontaining alloys or like materials, comprising an upper tank adapted tocontain the starting material in a molten state up to a given level andhaving an open upper part, and a substantially fiat bottom provided witha first and second opening, a bell shaped container having lateraldouble walls providing an internal space adapted to receive a moltenmetal and extending downwards into said tank through said open upperpart, below said level of said starting material, thereby forming areaction chamber within said tank, means for heating said tank and saidbell-shaped member, a gasdividing member tightly fitted in said firstopening, a supply conduit having one end adapted to be connected to asource of aluminum halogenide and another end opening under saidgas-dividing member and tightly connected to the bottom of said tank, anevacuation pipe passing through said second opening in a fluid tightmanner and having an upper end opening in the lower part of said tankthrough a gas-dividing member, an evacuation pipe passing through saidtank in a fluid-tight manner and having an upper end opening in theupper part of said reaction chamber above the level of the startingmaterial therein, and a lower end opening in a gas-tight decompositionchamber, a gas draw-0E pipe opening in said decomposition chamber and adraw-0E tank connected to said decomposition chamber beneath saidchamber, means being provided for heating said decomposition chamber anddraw-oil tank.

5. An apparatus for commercial extraction of aluminum from aluminumcontaining alloys or like materials, comprising an upper tank adapted tocontain the starting material in a molten state up to a given level, andhaving an open upper part, a bottom with a central raised portionencircling a single opening having walls extending a bell-shapedcontainer having lateral double walls providing an internal spaceadapted to receive a molten metal and extending downwards into said tankthrough said open upper part and resting upon said central raisedportion of the bottom of said tank, an annular gas-dividing membertightly fitted in said single opening in said raised portion of thebottom of said tank and having a substantially central opening, a supplyconduit having one end adapted to be connected to a source of aluminumhalogenide and another end opening under said gas dividing member andextending substantially axially between the walls of said single openingin said raised portion, an annular plug between said conduit and saidwalls of said single opening, an evacuation pipe arranged substantiallyaxially in said conduit and passing tightly through said central openingin said gas-dividing member, said evacuation pipe having an upper endopening in the lower part of said tank through a gas-dividing member, anevacuation pipe passing through said tank in a fluid-tight manner andhaving an upper end opening in the upper part of said reaction chamberabove the level of the starting material therein, and a lower endopening in a gas-tight decomposition chamber, a gas draw-ofi pipeopening in said decomposition chamber and a draw-01f tank connected tosaid decomposition chamber beneath said chamber, means being providedfor heating said decomposition chamber and draw-off tank.

6. An apparatus as claimed in claim 5, in which the bottom of said uppertank is supported on a bed of granular, heat insulating material carriedin a shallow circular tray having an opening for the passage of saidsupply conduit, said granular material also serving as a support forsaid annular plug.

7. An apparatus for commercial extraction of aluminum from aluminumcontaining alloys or like materials, comprising an upper tank adapted tocontain the starting material in a molten state up to a given level andhaving an open upper part and a bottom with a downwardly projecting,central portion contained by lateral walls of substantial depth andthickness and providing a single, central opening in said bottom, abellshaped container having lateral double walls providing an internalspace adapted to receive a molten metal and extending downwards intosaid tank through said open upper part and resting on said lateral wallsof said central portion, a supply conduit having one end adapted to beconnected to a source of aluminum halogenide and another end tightlyfitting in said opening in the bottom of the tank, an annulargas-dividing member tightly fitted in said other end of said conduit andhaving a substantially central opening, an evacuation pipe arrangedsubstantially axially in said conduit and passing tightly through saidcentral opening in said gas-dividing member, said evacuation pipe havingan upper end opening in the lower part of said tank through agas-dividing member, an evacuation pipe passing through said tank in afluid tight manner and having an upper end opening in the upper part ofsaid reaction chamber above the level of the starting material therein,and a lower end opening in a gas-tight decomposition chamber, a gasdraw-off pipe opening in said decomposition chamber and a draw-off tankconnected to said decomposition chamber beneath said chamber, meansbeing provided for heating said decomposition chamber and draw-off tank.

References Cited in the file of this patent UNITED STATES PATENTS2,697,597 Weiss Dec. 21, 1954

1. AN APPARATUS FOR COMMERICAL EXTRACTION OF ALUMINUM FROM ALUMIMUMCONTAINING ALLOYS OR LIKE MATERIALS, COMPRISING AN UPPER TANK ADAPTED TOCONTAIN THE STARTING MATERIAL IN A MOLTEN STATE UP TO A GIVEN LEVEL,FORMING A REACTION CHAMBER HAVING A GAS-TIGHT UPPER PART, MEANS FORHEATING SAID TANK, A SUPPLY CONDUIT ADAPTED TO BE CONNECTTED TO A SOURCEOF ALUMINUM HALOGENIDE OPENING IN THE LOWER PART OF SAID TANK THROUGH AGASDIVIDING MEMBER, AN EVACUATION PIPE PASING THROUGH SAID TANK IN AFLUID-TIGHT MANNER AND HAVING AN UPPER END OPENING IN THE UPPER PART OFSAID REACTION CHAMBER ABOVE THE LEVEL OF THE STARTING MATERIAL THEREIN,AND A LOWER END OPENING IN A GAS-TIGHT DECOMPOSITION CHAM-